By the time the sun came up Friday, 21 fires had been reported in Hollywood and West Hollywood, the Los Angeles Times reported. Most were started in parked cars and, in many cases, spread to houses or apartment buildings.
The Hollywood Hills house where Jim Morrison, lead singer of the Doors, once lived was among the damaged buildings. The house inspired his song "Love Street."
Investigators questioned Samuel Arrington, 22, who was arrested Thursday on suspicion of starting three fires on Sunset Boulevard early Friday. They were trying to determine whether someone with ties to Arrington was responsible for the new arsons.
"It's too early to say whether we have a copycat," Fire Capt. Jaime Moore said.
Fire officials said more than one person may have been involved because some of the fires were reported within minutes of each other and several miles apart.
Meanwhile, a total of $60,000 in reward money has been offered for information leading to the arrest of a suspect or suspects in the arsons, officials said.
County Supervisor Zev Yaroslavsky announced a $25,000 reward. An additional $10,000 is being offered from the federal government and $25,000 from other sources, Yaroslavsky said.
"We are dead serious about apprehending the individual or individuals responsible for this," Yaroslavsky said. "We want to get these SOBs before they hurt somebody."
2014: The Year in Music [PHOTOS]